On 3/4/15 1:31 PM, Soni M wrote:
Hello All, Master db size 1.5 TB All postgres 9.1.13 installed from RHEL package. It has streaming replica and slony replica to another servers. Server performance is slower than usual, before that, there's a big query got cancelled and then performance get slow. No sign of IO wait. on sar, it's %user and %system dominate the cpu usage 01:25:04 PM CPU %user %nice %system %iowait %steal %idle Average: all 51.91 0.00 12.03 0.66 0.00 35.39 on perf top, i saw 18.93% postgres [.] s_lock 10.72% postgres [.] _bt_checkkeys almost always at top.
_bt_checkkeys is the function that compares a row in a btree index to a condition. s_lock is a spinlock; the high CPU usage in there indicates there's heavy lock contention somewhere.
Is there one PG process that's clearly using more CPU than the others? What else is running in the database? Are there any unusual data types involved?
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